M939 Stop Switch Questions...

[The HUlk]

my hypothesis, assuming wiring is unmolested, is that this problem is in the fuse panel. But again that should mess with the trailer lights. There is of course the rare oddity that all 4 lights have the running bulb burnt out or bad grounds, but should that not also affect the blinkers brake and turn? And like we discussed earlier should it be the 3 lever then why are my trailer lights working. All should be answered tomorrow on my day off!

Fuse panel is a good guess, however there isn't one lol. There are a few (5?) fuses hidden here and there but I'm confident that is not the problem. There is no fuse for seperate lighting functions. All of the exterior lights are powered from the same supply through the light switch. The brake and turn signals use the same bulb/filament which is different from the bulbs used for tail/markers. Also, If the ground on a light is bad then you would have no brake lights or turn signal because a single ground is used for all of the bulbs in each light assembly. I strongly reccomend jumping the circuit at the light switch as a first step. If the tail/running lights work with the jumper then try a known good light switch.